Solve for $n$ : $18 + n = -5$
Subtract $18$ from both sides: $ \begin{eqnarray} \\ 18 + n &=& -5 \\ \\ {-18} && {-18} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{18 + n} &\hphantom{=}& \hphantom{-5} \\ n &=& -5 {- 18} \\ \end{eqnarray} $ Simplify. $ n = -23$